Devices for measuring forces in a moving strip



Nov. 5, 1968 DEVICES FOR MEASURING FORCES IN A MOVING STRIP Filed Aug.10, 1965 J. R. GUINGAND I 2 Sheets-Sheet 1 w ,R. mm mm a \w @m ww mmNov. 5, 1968 J. R. GUINGAND 3,408,863

DEVICES FOR MEASURING FORCES IN A MOVING STRIP 2 Sheets-Sheet 2 FiledAug. 10, 1965 United States Patent Oifice 3,408,863 Patented Nov. 5,1968 Claims. ((51. 73-444 ABSTRACT OF THE DISCLOSURE A device formeasuring the tension in a moving strip by passing the strip around aroll which is rotatably mounted on a pair of hollow shafts which in turnare mounted, via ball and socket joints, at the center of an internalstationary shaft. An adjustable force measuring cell is mounted in aguide which is secured between the stationary shaft and each hollowshaft in a plane which bisects the angle of wrap of the strip on theroll such that the cell produces a measurement of force related to thetension in the strip in response to relative displacement of the hollowshafts with respect to the stationary shaft.

It is necessary in various arts, and particularly in the art ofprocessing continuous sheet-metal strip, to measure not only themovement of the strip but also the forces exerted in such moving strips.The main forces involved are the tension exerted on the strip and thelateral force tending to deviate it from its line of travel.

The present invention relates to an apparatus for permitting suchmeasurements in a simple way.

The invention accordingly provides, for the measurement of forces,dynamometric cells positioned adjacent the ends of a shaft supporting aroll over which a strip runs, compensating means being provided forcalibrating said cells.

The invention further provides, for the purposes of measuring thetension in such a strip, a roll about which the strip is partly wrapped,which is mounted slidably in the plane bisecting the angle of wrap andwhich is associated with dynamometric cells for measuring the forcesdeveloped in said bisectin plane.

For the purpose of measuring lateral forces, compensating means areprovided for centering the roll upon the axis of a line, together withelastic compressing means for automatically taking up any play which maydevelop in the system of anti-friction bearings associated with theroll.

In both cases the dynamometric cells may be coupled to direct read-outdials, or to recording or counting readout devices, or else to aservo-system for activating control means of the tension and/or thedirection of travel of the strip whereby to prevent, in particular, agiven maximum tension from being exceeded.

In one specific form of embodiment, the force measuring device comprisesa roll supporting a strip and mounted through the medium ofanti-friction bearings and thrust bearings if need be, on a fixed shaft.

Where it is required to measure the tension in a strip, a roll having astrip wrapped partially around it is mounted through the medium oflateral anti-friction bearings on two hollow shafts surrounding saidfixed shaft, which shafts are supported adjacent the centerplane of theroll rim by means of ball-and-socket joints on said inner fixed shaft,the dynamometric cells being interposed, externally of said roll,between the corresponding ends of the hollow shafts and the facingportion of the fixed shaft.

Prismatic housings rigid with the ends of the hollow shafts contain saidcells and form a guideway parallel with said bisecting plane, incooperation with matching blocks rigidly connected to the fixed shaft.

Adjustable elastic means are interposed, opposite the cells, between thefixed shaft and the hollow shaft in order to compensate for the effectof gravity on the weight of the roll and its ancillaries-notably thehollow shafts.

Where it is desired to measure lateral forces, a roll of this type ismounted on such a fixed shaft through the medium of anti-frictionbearings and thrust bearings, said fixed shaft having hollow ends formedwith traverse openings therein which receive bars and thrust pins fortransmitting the lateral forces to dynamometric cells adjustably mountedin end housings of said fixed shaft.

The description which follows with reference to the accompanyingnon-limitative exemplary drawings will give a clear understanding of howthe invention can be carried into practice.

In the drawings:

FIG. 1 shows in schematic section a device for measuring the lateralforce in an advancing strip;

FIG. 2 shown on a reduced scale and in schematic section a device formeasuring the tension in a strip;

FIG. 3 is a section on the line IIIIII of FIG. 2;

FIG. 4 is an alternative embodiment of the device of FIG. 2; and

FIG. 5 is a section on the line VV of FIG. 4.

The device shown in FIG. 1 comprises a roll having a cylindrical rim 1assembled on lateral flanges 2 and 3 which bear against the outer races4 and 5 respectively of roller bearings 6 and 7 of which the inner races8, 9 are supported on corresponding bearing surfaces against stepsformed on a fixed shaft 10. The outer races 4 and 5 of theseantifriction bearings are slidable in both directions, in parallelismwith the axis of the roll, on the rollers 6 and 7. The ends of the shaftare retained in and keyed to lateral supports 11 and 13.

The flanges 2 and 3 are rigidly connected to bells 13 and 14 theperforated bottoms of which support the inner races 15, 16 of thrustball-bearings of which the outer races 17 and 18 are applied againstexternal trans verse bars 19 and 20. Said bars extend with clearancethrough transverse openings 21 and 22 formed in the ends of the shaft10. These shaft ends are hollow and the voids therein open out into saidopenings.

On one side, for instance on that of the bar 20, the hollow end receivesagainst said bar an internal pointed pin 23 against which presses aspring 24 the other end of which bears against a further pin 25protruding into a housing 26 rigid with the corresponding end of theshaft 10. The housing 26 has mounted slidably therein a cup 27containing a dynamometric cell 28 the pointed moving element 29 of whichpresses against the outer protruding end of pin 25, in response to anadjustment screw 30 mounted in the bottom 31 of housing 26, providedwith an outer knob or adjustment head and thrusting against the rear ofcup 27.

On the other side, the bar 19 bears against a rigid pin 32a which is inturn applied against the pointed end 32 of the moving element of adynamometric cell 33 mounted in similar fashion in a cup 34 which isslidable in a housing 35 connected to the corresponding end of shaft 10,said cup bearing against a similar adjustment screw 36 screwed into thebottom 37 of housing 35.

The lateral forces exerted on the strip rolling over the roll 1 aretransmitted to the rim thereof by adhesion. The displacements aretransmitted by the thrust ball-bearings and retransmitted directly tothe dynamometric cells 28 and 33. The spring 24 neutralizes any backlashin these thrust bearings. The screws 30 and 36 serve both to calibratethe cells in conjunction with the spring 24 (the degree of compressionof which is thereby adjusted), and to center the roll on the axis of thepath of travel of the strip. Provision may be made for a dial giving adirect reading by means of the dynamometric cells, or else the lattermay be connected directly or indirectly to recording and/or countingdevices, or even to a servomechanism for correcting the travel of thestrip where necessary.

With regard to the tension measurements, as may be seen on FIGS. 2 and3, a rimmed roll 38 is positioned at a point of change of direction inthe path of a strip 39 whereby the latter is caused to wrap itselfaround the rim 38 over a given sector. The roll is mounted through themedium of flanges 40, 41 on anti-friction bearings 42 and 43. Thebearing 42 is supported on a hollow shaft 44 through which extends withclearance at fixed shaft 45 the ends of which are retained in and keyedto external supports 46.

Adjacent the middle of shaft 45 is positioned a block 47 having aspherically contoured periphery which slidably receives thereon a liner48 of matching contour rigidly connected to the inner end of hollowshaft 44.

Externally of flange hollow shaft 44 receives a housing 49 ofrectangular internal shape which is guided over a matching prismaticblock 50 rigid with shaft 45, the plane of symmetry of the whole lyingin the plane bisecting the angle of wrap of the strip about the roll.Ball type anti-friction guide means 51 may be interposed if requiredbetwene housing 49 and block 50. The latter is keyed to shaft in orderto ensure its fixed position.

Between one end closure 52 of housing 49 and the facing side of block isinterposed a dynamometric cell 53. The block 50 is rigidly connected toa draw-link 54 at its end remote from cell 53, and this draw-linkextends through the end closure 55 remote from end closure 52 andreceives a nut 56 which engages with a threaded portion on thedraw-link. A spring 57 is interposed between nut 56 and end closure 55.

The roll 38 is mounted symmetrically and the opposite side is equippedwith identically disposed components.

In this particular arrangement the strip 39 passes over the top of theroll 38.

If, as shown in FIGS. 4 and 5, a strip 59 passes over the undersurfaceof the rim 58 of a similar roll, then the general arrangement will bemodified only insofar as the mutual positioning of the dynamometriccells and the spring is concerned. For in the corresponding housing 60the dynamometric cell 61 is still located on the side nearer the arc ofwrap of the strip, but a spring 62 in the housing 60 is interposedbetween a bearing plate 63 terminating a screw 64 and the correspondingblock 65 rigid with the fixed shaft 450, said screw being screwed intothe bottom of housing 60.

In both cases the spring 57 (or 62) is used to counter the effect, onthe measurement, of gravity exerted on the mass of the roll and itsancillaries. In the case of FIGS. 2 and 3 this spring externallydisposed balances said mass in compression, as in that of FIGS. 4 and 5the internal spring 62 relieves the cell of the weight of the roll andits ancillaries.

A mathematical expression for the leverage exerted relates the value ofthe tension in the strip to the force applied to a dynamometric cell.These leverages are, on the one hand, the distance between the plane offlange 40 and the center of the ball-and-socket joint 47 and, on theother, the distance between said center and the plane containing thepoint of application of the moving element of the dynamometric cell onthe corresponding block.

Further, a trigonometric relationsnhip exists between the tension in thestrip, the force exerted on a cell and the angle of wrap of the stripabout the roll.

Provision may be made for a single measuring instrument with a read-outdial for the two dynamometric cells of the same measurement roll,irrespective of the disposition thereof with respect to the strip. Asstated precedingly, such an instrument equipped with a direct readoutdial may be replaced with or associated to recording or computingdevices, or possibly even to a servomechanism operating on elementsadapted to adjust the tension in the strip. 1

It goes without saying that many changes and substitutions of parts maybe made to the specific forms of embodiment hereinbefore describedwithout departing from the scope of the invention, as defined by thehereunder appended claims. v

What I claim is:

1. In a device for measuring tension forces exerted on a moving strip,in combination, a stationary shaft having opposite ends, a roll uponwhich said strip is applied according to a given angle of wrapping, apair of hollow shafts interposed between said roll and said stationaryshaft, a pair of lateral flanges secured to said roll, bearingsrotatably supporting each of said flanges on a corres ponding hollowshaft, ball and socket joints between internal extremities of each saidhollow shaftand a central portion of said stationary shaft, guidingmeans secured between said stationary shaft and each of said hollowshafts in the vicinity of the ends of said stationary shaft, saidguiding means being disposed parallel to the bisecting plane of saidwrapping angle, force measuring means mounted in said guiding meansbetween said stationary shaft and each said hollow shaft for producing ameasurement of force related to the tension in the strip, in response torelative displacement of the hollow shafts with respect to thestationary shaft, and means engageable with said force measuring meansfor the calibration thereof.

2. In a device for measuring forces exerted on a moving strip accordingto claim 1, wherein said guiding means each comprises one block keyed onsaid stationary shaft, presenting guiding faces parallel to saidbisecting plane, one housing surrounding said corresponding block andpresenting guiding surfaces operatively cooperating with said guidingfaces of said block, each said force measuring means being adynamometric cell being interposed between an end face of said block anda corresponding bottom of said housing.

3. In a device for measuring forces exerted on a moving strip accordingto claim 2, anti-friction devices interposed between said guiding facesof said block and guiding surfaces of said housing.

4. In a device for measuring forces exerted on a moving strip accordingto claim 1, wherein the means for the calibration of each cell compriseselastic means interposed externally between a bottom of said housing andan ad'- justable abutment member fitted at the end of a drawlinkintegral with a corresponding block and projecting through said bottom.

5. In a device for measuring forces exerted on a moving strip accordingto claim 1, wherein the means for the calibration of each cell compriseselastic means interposed internally between an end face of said blockand an adjustable abutment member carried by a corresponding bottom ofsaid housing.

References Cited UNITED STATES PATENTS I 1,168,925 1/1916 Zanzig 73-1 442,582,886 1/1952 Ruge 73-141 2,974,894 3/1961 Aaron 24275.43 3,260,1067/1966 Hull et a1 73.-144

FOREIGN PATENTS 576,760 5/ 1924 France. 964,137 7/ 1964 Great Britain.

RICHARD C. QUEISSER, Primary Examiner.

J. H. WILLIAMSON, Assistant Examiner.

